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Slav-nsk [51]
3 years ago
7

In the construction of bridges and sky scrapers, gaps must be left between adjoining steel beams to allow for expansion and cons

truction of the metal due to heating and cooling. The temperature of a sample of iron with a mass of 20.0 grams changed doom 60.0 C to 35.0c. How many joules of heat were released? A. 200 joules B. 225 joules C. 152 joules d. 346 joules
Chemistry
1 answer:
PSYCHO15rus [73]3 years ago
4 0

Answer:

Q = -225 J

Explanation:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Given data:

Mass of iron = 20 g

Initial temperature = 60 °C

Final temperature = 35 °C

Heat released = ?

Solution:

Q = m.c. ΔT

Specific heat of iron = 0.46 j/g. °C

ΔT  = 35 °C - 60 °C

ΔT  = -25 °C

Q = 20 g× 0.450 j/g. °C× -25 °C

Q = -225 J

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When sodium phosphate reacts with sulfuric acid, forming sodium sulfate and phosphoric acid, the stoichiometric coefficient for sulfuric acid in the balanced chemical equation is 3.

In every balanced chemical equation, the total number of individual atoms on the reactant side must be equal to the total number of individual atoms on the product side. The stoichiometric coefficient is the number written in front of each reactants and products that tells how many moles of each are needed in the reaction.

The chemical equation for the given reaction is:

Na_{3} PO_{4} + H_{2} SO_{4} = Na_{2} SO_{4} + H_{3} PO_{4}

Put the necessary stoichiometric coefficient to balance each element.

Balancing Na:

2Na_{3} PO_{4} + H_{2} SO_{4} = 3Na_{2} SO_{4} + H_{3} PO_{4}

Balancing P:

2Na_{3} PO_{4} + H_{2} SO_{4} = 3Na_{2} SO_{4} + 2H_{3} PO_{4}

Balancing S:

2Na_{3} PO_{4} + 3H_{2} SO_{4} = 3Na_{2} SO_{4} + 2H_{3} PO_{4}

Notice that H and O are already balanced.

Hence, the balanced chemical equation for the reaction is:

2Na_{3} PO_{4} + 3H_{2} SO_{4} = 3Na_{2} SO_{4} + 2H_{3} PO_{4}

where 3 is the stoichiometric coefficient of sulfuric acid, H_{2} SO_{4}.

Learn more about stoichiometric coefficient here: brainly.com/question/6666875

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1 year ago
Lichens are an example of a(n)
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Lichens are an examples of Symbiosis
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How many protons electrons and neutrons respectively does 29 CS have
irakobra [83]

55 \; \text{e}^{-}, 55 \; \text{p}^{+}, and 74 \; \text{n}^{0}- in case cesium-129 is what you were referring to.

Cesium has atomic number 55 as seen on a modern periodic table. A cesium atom nucleus would thus contain an equal number of protons; in addition to that, a <em>neutral</em> atom of cesium would contain the same number of electrons in its electron cloud.

For a particular isotope,

\text{Mass number} = \text{Number of protons per nuclei} + \text{Number of Neutrons per nuclei}.

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8 0
3 years ago
Can someone help me I would really appreciate it
slega [8]
The condensed formula would be CH3-CH(CH4)-CH2-CH(CH4)-CH2-CH(CH4)-CH3. The molecular formula would be C10H25.
8 0
4 years ago
Calculate the average atomic mass for the following element given information about the relevant isotopes: (Isotope 1) Mass = 20
polet [3.4K]

Answer:

The average atomic mass of given element is 20.18 amu.

Explanation:

Given data:

Abundance of 1st isotope mass 20 amu = 90.92%

Abundance of 2nd isotope mass 21 amu = 0.257%

Abundance of 3rd isotope mass 22 amu = 8.82%

Average atomic mass = ?

Solution:

Average atomic mass  = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass)  / 100

Average atomic mass  = (90.92×20)+(0.257×21)+(8.82×22) /100

Average atomic mass =  1818.4 + 5.397 +194.04 / 100

Average atomic mass  = 2017.819 / 100

Average atomic mass = 20.18 amu.

The average atomic mass of given element is 20.18 amu.

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